Heat distributing apparatus



June 1956 H. A. OLDENKAMP ETAL 2,752,144

EAT DISTRIBUTING APPARATUS 2 Sheets-Sheet 1 Filed June 4, 1951 INVENTOR HENRY A. OLDENKAMP BY PHILIP KAFTOL ATTORNEY June 26, 1956 H. A. OLDENKAMP EI'AL 2,752,144

HEAT DISTRIBUTING APPARATUS 2 Sheets-Sheet 2 Filed June 4, 1951 INVENTOR HENRY A. OLDENKAMP PHILIP KAFTOL HEAT DISTRBUTHVG APPARATUS Henry A. Oldenkamp, Valhalla, and Philip Kaftol, Brooklyn, N. Y., assignors to American Machine & Foundry Company, a corporation of New Jersey Application June 4, 1951, Serial No. 229,742

6 Claims. (Cl. 26319) This invention relates to heat distributing apparatus and more particularly to apparatus which is adapted for use with oil, coal, or gas burners such as are employed in tobacco curing barns.

Heat distributing apparatuses heretofore designed have had various disadvantages. In some instances the skin temperatures of the heat distributing apparatus have in operation become so high that they constitute a fire hazard and result in tobacco barns being burned down. In other cases, the heat distributing apparatus, because of the great amount of heat they have to carry and handle, literally burn up, and disintegrate. This is not only unsatisfactory but in and of itself could also be a considerable fire hazard if not noticed. Where heat distributing apparatuses are constructed of highly refractory material they do not burn up but the structures are massive, expensive, and obviously are not portable.

It is an object of this invention to provide a heat distributing apparatus for use in a tobacco curing barn which is portable and will not deteriorate in operation.

Another object of this invention is to provide a heat distributing apparatus which will enable a tobacco barn to be adequately heated without having the heat conducting ducts attain skin temperatures which constitute a fire hazard.

A further object is to provide a heat distributing apparatus which may be shipped as a packaged unit into the field, which may be easily set up in a tobacco curing barn without any skilled assistance, and which will be of durable construction.

A further object is to provide a heat distributing apparatus which will be of lightweight construction and which can be economically manufactured and shipped and yet be durable so that it will not deteriorate in the normal course of operation.

Another object of this invention is to provide a heat distributing apparatus which will effect a uniform distribution of heat throughout the tobacco curing barn.

Another object is to provide a heat distributing apparatus for use with a direct fired forced air system which can be damper controlled for curing tobacco in a tobacco curing barn.

Another object is to provide a heat distributing apparatus which may be easily and readily adapted to compensate for varying heat loss factors in the particular tobacco curing barn in which it is installed.

Another object is to provide a central heat distributing chamber which will difl'use heat throughout the system while avoiding the emission of combustion flames into the distributing arms of the apparatus.

Other objects and features of the invention will appear as the description of the particular physical embodiment selected to illustrate the invention progresses. In the accompanying drawings, which form a part of this specification, like characters of reference have been applied to corresponding parts throughout the several views which make up the drawings.

States atent 2,752,144 Patented June 2%, 1955 Figure 1 is an isometric view, partly in section, showing the octagonal prefabricated fire box in connection with the tapered combustion chamber.

Figure 2 is a sectional end elevation through one of the tubular metal duct distributors illustrating one of the dampers in the duct.

Figure 3 is an isometric view illustrating the heat distributing apparatus in conjunction with a jet type oil burner.

There are two principal types of tobacco curers, namely, direct fired curers and indirect fired curers. In a direct fired curer, the hot combustion gases are discharged directly into the tobacco curing barn. In an indirect fired tobacco curer, the hot combustion gases are conveyed through ducts and are discharged outside of the barn through a fine pipe. In the latter case, the combustion gases contained combustion products which would be harmful to the tobacco leaves if discharged into the barn. Heat is removed from the gases in such a case by radiation from the ducts through which the hot gases are led to the flue pipe.

It takes a predetermined quantity of heat to cure tobacco. Where heat is lost up a chimney, as in an indirect fired curer, it is necessary to deliver that additional number of B. t. u.s into the radiation ducts so as to be certain that there is enough heat released in the tobacco curing barn to cure the tobacco. There are various types of direct fired burners on the market which will permit the combustion gases to be discharged directly into the tobacco curing barn. Co-pending applications S. N. 179,- 710 and S. N. 216,180 filed by Henry A. Oldenkamp on August 16, 1950, and March 17, 1951, respectively, describe and illustrate some of the most recent burners developed for this purpose. In the latter type of burner, the fuel products undergo complete combustion so that no objectionable combustion products are discharged into the tobacco curing barn.

Regardless of whether an indirect fired curer or a direct fired cur-er is employed, there is a considerable amount of heat that must be handled by the distributing apparatus. It is well recognized that any type of heating apparatus must be designed so as to maintain the skin temperatures of the heat transfer surfaces at a safe limit to avoid becoming a fire hazard. This is accomplished by providing enough heat transfer surface so as to lower the heat per square foot of transfer area to safe limits at any point of the heat transfer apparatus.

The unit into which the hot combustion gases are discharged from the burner, regardless of whether the burner be coal, gas, or oil, is sometimes referred to as a firebox. This unit must be of such design as to be capable of standing up under the temperatures required for a tobacco curing barn, and for the duration, and under the operating conditions normally prevailing in curing tobac co. The life expectancy of such a firebox should be at least as long as that of a durable goods item such as a burner used for curing tobacco in a barn.

The best type of curing apparatus is one that has the lowest skin temperatures over-all and is capable and best able to cure tobacco satisfactorily in all portions of the tobacco curing barn. In meeting these requirements, the firebox must be large enough to receive all the heat required and to distribute the heat through an apparatus which will have low skin temperatures. A firebox meeting these requirements will have a wide ceiling area. The firebox should also be of lightweight construction, easily assembled in the field, and must be lightweight to permit economical shipment by the manufacturer to the user.

A firebox constructed in the field out of refractory material, while it is durable in construction, is uneconomical to ship, it is not adaptable for sale as a packaged unit, and often requires skills and materials in construction that are not always available in the area where the burner is to be installed.

The present invention, which will now be described, 7

meets the requirements outlinedabove, and consists chiefly of a firing tube or combustion chamber C, a firebox F, and a plurality of tubular sheet metal ducts .or.pipe D connected to said firebox F. The firing tube C comprises a tubular metal shell 1% having a lining of suitable refractory material 12 such as vermiculite. This firing tube C may be formed, if desired, with an internal taper such as indicated by the reference character 14. The tapered channel has the advantage that it may be more readily cast and the tapered center opening provides a gradually increasing cross-sectional area which provides room for the expanding gases and thereby permits a more gradual fiow of gases through the distributing apparatus.

Aspreviousl-y mentioned, applicants apparatus is adaptable for use with either gas, coal, or oil. For purposes ofillustration, applicants have shown how their apparatus may be adapted for use with an oil burner.

The nozzle portion 16 of the jet type oil burner B, such as referred to hereinabove, is connected to the narrow end of duct 14 and the wider end of duct 14 is connected with the inner chamber 18 of the firebox F. The firebox consists of a metal shell 20 which is similar to an inverted bowl. The floor under the inverted bowl is provided with a sheet of metal 22. The roof, or ceiling 28, and the inner sides of the shell, are lined with a high temperature plastic vermiculite compound such as Mascote manufactured by the Vermiculite Industrial Corporation of Port Newark, N. J., or Wyolite manufactured by Wyodake Corporation of Cleveland, Ohio. If desired, the metal sheet'22 may be similarly coveredwith Mascote or with vermiculite. The ceiling of the shell is supported by a metal spider 26.

Mascote is secured to the sides and ceiling of the firebox by means of a suitable screen such as 19 and 30. These screens 19 and 30 are secured to the walls 20 and spider 26 by suitable means such as welding. When Mascote is applied to the screening 19 and 30;, this provides a firm foundation to which the Mascote can adhere, and also provides the Mascote with rigidity and strength.

Since Mascote is a substantially plastic substance that does not completely solidify, itis desirable to coat the ceiling 28 of the firebox F with a layer of Portland cement or hard refractory cement and vermiculite aggregate to provide a hard and fairly durable top surface 32 to the ceiling 28. 7

Five sides of the octagonal firebox F are provided with openings 34 Tubular metal ducts 36 are connected at one end to each of said openings 34. The other end of each of said metal ducts are provided with 90 degree elbows 38 the open end of which faces upwardly and carries a baffleor heat distributing plate 40. The latter is removably attached to the elbow by means of suitable spaced lugs 42 (Fig. 3).

It has been found that a plastic-like substance such as Mascote and Wyolite will not harden when the curing system is in operation and consequently it does not dry up and crack or disintegrate as occurs when other types of materials are employed.

Since during operation the initial four or five feet of each duct 36 closest to the firebox is much hotter than the remaining portion of these ducts, there is provided a suitably shaped shield 44 over this portion of each duct 36. These shields act as a heat distributor as well as a safeguard in case particles of tobacco leaf should accidentally fall on this portion of the duct. Shields 44 are suitably attached to and supported by extensions 46 which may be formed integrally with suitable legs or supports 48 so as to support each duct above the floor or ground of the building.

Each duct 36 is provided with an adjustable self-locking damper (Fig. 2) which consists of a damper P at 50 secured to a vertical rod 52 projecting through each duct. A suitable handle 54 is provided for adjusting the damper 50. To prevent the duct 36 from being completely closed by said dampers 59, the damper plates 50 are smaller in diameter than the inside diameter of the duct 36 so that combustion gases can pass by the damper when the damper is in closed position. It will be noted, however, that the damper 50 is mounted so that it is positioned closely adjacent to the upper end of the duct 36 and thus effectively blocks the hottest portion of the gases. To obtain a uniform distribution of heat from the firebox F into all of the heat distributing ducts 36 and to prevent flames from escaping through the openings 34, the chamber '18 of the firebox F is provided with a; curved, perforated shield or bafiie 56. The portion of the shield which is immediately in front of the firing tube 10 is provided with an imperforate portion or vertical plate 58. The baffle 56 is adjustably attached to the bottom portion of the firebox by means of a bolt 60 which travels in a suitable slot 62 in the bottom portionof the firebox.

Since tobacco curing barns often have uneven heat losses in different portions of the tobacco curing barn, the tubular metal ducts may be readily lengthened .or shortened in the barn to compensate for such losses. The dampers 50 also provide an adjustment to compensate for such varying heat losses. sate for varying heat losses is to raise or lower the end of the .duct38 so as to make it incline and this slope will either hasten or retard the flow of gases through the ducts.

Because of the nature of the particular type of tobacco leaf being cured, it is often necessary to make careful adjustments of the method of distributing heat in the to bacco curing barn. These adjustments are sometimes due to the fact that tobacco leaf is unevenly stacked in the tobacco curing barn or the barn has or is of such construction as to require special heating arrangements. The change in heat, therefore, in the barn may have to be faster or slower in one section than in another.

The dampers 51} will generally give slow changes in temperature within the a range of from 5 to 8 degrees fahrenheit in one portion of the barn at some thermostat setting within one hour.

For faster changes, the end covers 40 are raised, 10wered, .or tilted so as to effect the variation in temperature desired. By regulating the space between the open end of the elbow 38 and the cover 4%, the amount of heat allowed to escape through the duct B may be regulated. Heat is directed by tilting the covers 40. These adjustments are .rnade :by pushing the holding brackets together sothat they slide inside-of the open end of elbow 38.

The invention above described may be varried in construction within the scope of the claims, for the particular device selected to illustrate the invention is but one of many possible embodiments of the same. The invention, therefore, .is not to be restricted to the precise details of the structure shown and described.

What is claimed is:

1. A tobacco curing barn heat distributing apparatus having a fire box made of refractory material having openings extending laterally from said firebox, a firing tube rnade'of refractory material connected to one of said openings forconducting gases in the process of corn-v bustion to said firebox, a perforated bafile positioned vertically inside of said firebox and transversely in front of the gases undergoing combustion as they are discharged through said firing tube, said baffle being constructed and arranged to prevent the escape of flame out through said openings and, heat distributing ducts made of sheet metal connected to each of said openings for conducting heat from said firebox to the outer area of the tobacco curing rn- 2. A heat distributing apparatus for distributing the hot combustion gases received from a fuel burner across the floor [of a tobacco curing barn, said apparatus com prising, a firebox having a plurality of openings formed Another way to compenin the sides thereof, heat distributing arms connected to each of said openings, a perforated vertical shield mounted transversely inside of said firebox in front of said openings to prevent flames from escaping into said heat distributing arms, a fuel burner, a firing tube interconnecting said burner with said fire box and being positioned in substantially the same plane as said openings, said firing tube being made of a refractory material adequate to Withstand the temperatures of said combustion gases and said firebox having a lining made of vermiculite, an elbow positioned on the end of each of said arms and extending upwardly to allow gases to escape at the ends of said arms, and a flat metal disc spaced above the discharge openings of said elbows for deflecting heat escaping therefrom.

3. A heat distributing apparatus for distributing the hot combustion gases received from a fuel burner across the floor of a tobacco curing barn, said apparatus comprising a hollow flat firebox having separate openings formed in the periphery of said firebox, sheet metal ducts connected to each of said openings for conducting hot combustion gases away from said firebox, a perforated shield positioned across the path of travel of said hot combustion gases to prevent flame from being discharged into said sheet metal ducts, a firing tube mounted in the same plane as said openings for connecting said fuel burner with said firebox, a burner for discharging hot combustion flames into said firing tube, an elbow mounted on the end of each of said metal ducts and turned to extend upwardly from the ducts, a flat horizontal disc positioned above and spaced from the open end of each of said elbows, and a damper mounted in each of said sheet metal ducts at the far end of said elongated sheets of metal for individually regulating the amount of gas flowing through each of said ducts.

4. A heat distributing apparatus comprising, a burner, 21 firing tube, a firebox having an outer shell made of sheet metal, a foraminous lining attached to the inside surfaces of said outer shell, means supporting said foraminous lining over the top of said outer shell to form a ceiling, a high temperature plastic vermiculite compound spread across said foraminous lining to coat the inside of said firebox with a heat resisting insulating material, sheet metal pipes connected to said firebox in the same plane as said firing tube for distributing hot combustion gases received from said firebox across the area of a chamber to be heated, and a vertical perforated shield spaced from said lining and positioned in the arc in front of said firing tube, said shield having an area in front of said firing tube which is imperforate to prevent gases from being positioned directly into distributing arms positioned in front of said firing tube.

5. A heat distributing apparatus comprising, a framework constructed and arranged to form a bowl, a sheet of metal extending across the entire open side of said bowl, a perforated lining secured to the inside of said bowl, a ribbed structure positioned across the ceiling of said inverted bowl to support said perforated lining, a high temperature plastic vermiculite compound spread over said perforated lining to form a heat insulating material on the inside of said firebox, a vertical perforated baflie positioned inside of said firebox, a firing tube connected to the side of said firebox which is opposite to the perforated baflie, and distributing orifices formed in said firebox for distributing heat from said firebox uniformly through each of said orifices, said orifice being in substantially the same plane as said firing tube.

6. A heat distributing apparatus comprising, a box having a metal framework With orifices all formed in the same plane in the sides thereof, a perforated sheet metal lining connected to the inside surfaces of said box, a high temperature plastic vermiculite compound spread over said perforated sheet metal lining to form a heat insulated firebox, radiating ducts connected with said orifices at one end and having an elbow opening upwardly mounted on the discharge end of the opposite end of said ducts, a deflecting plate positioned above each of the openings at the end of said ducts to deflect heat laterally, a spider for supporting the ceiling of said box, a mixture of hard cement and vermiculite spread across the top and outside of said firebox, and a firing tube connected to one of the orifices formed in said firebox for discharging hot combustion gases into said firebox.

References Cited in the file of this patent UNITED STATES PATENTS 192,395 Todd June 26, 1877 1,487,689 Manning Mar. 18, 1924 1,993,251 Surry Mar. 5, 1935 2,138,998 Brosius Dec. 6, 1938 2,210,301 Neuby Aug. 6, 1940 2,296,392 Marchant Sept. 22, 1942 2,376,873 Henderson May 29, 1945 2,533,092 Chestnutt Dec. 5, 1950 2,551,215 Lytton May 1, 1951 2,562,601 Caquot et al. July 31, 1951 2,631,782 Thomas Mar. 17, 1953 2,670,191 Furth Feb. 23, 1954 FOREIGN PATENTS 468,672 Canada Oct. 10, 1950 

